4 - ORYSTALLOGRAPITY. 
1. CRYSTALLIZATION OF MINERALS: 
CRYSTALLOGRAPHY. 
1. GENERAL REMARKS ON CRYSTALLIZATION. 
THE attraction which produces crystals is one of the funda: 
mental properties of matter. It is identical with the cohesion 
of ordinary solidification ; for there are few cases outside of the — 
kingdoms of life in which solidification takes place without some 
degree of crystallization. Cohesive attraction is, in fact, the 
organizing or structure-making principle in inorganic nature, it 
producing specific forms for each species of matter, as life does 
for each living species. A bar of cast-iron is rough and hackly 
in surface, because of the angular crystalline grains which the 
iron assumed as solidification took place. A fragment of mar- 
ble glistens in the sun, owing to the reflection of light from in- 
numerable crystalline surfaces, every grain in the mass having 
its crystalline structure. When the cold of winter settles over 
the earth in the higher temperate and colder latitudes it is the 

CRYSTALS OF SNOW. 
signal for crystallization over all out-door nature; the air is 
filled with crystal flakes when it snows; the streams oecome 
coated with an aggregation of crystals called ice; and windows 
are covered with frost because crystal has been added to crystal 
